How the F.B.I. Cracked a Chinese Spy Ring

In the magazine earlier this month, I wrote about Greg Chung, a Chinese-American engineer at Boeing who worked on NASA’s space-shuttle program. In 2009, Chung became the first American to be convicted in a jury trial on charges of economic espionage, for passing unclassified technical documents to China.

While reporting the story, I learned a great deal about an earlier investigation involving another Chinese-American engineer, named Chi Mak, who led F.B.I. agents to Greg Chung. The Mak case, which began in 2004, was among the F.B.I.’s biggest counterintelligence investigations, involving intense surveillance that went on for more than a year.

The stakes were high: at that time, the F.B.I. did not have a stellar record investigating Chinese espionage. Three years earlier, the government had been publicly humiliated by its failed attempt to prosecute the Chinese-American scientist Wen Ho Lee on charges of passing nuclear secrets from the Los Alamos National Laboratory to China, in a case that came to be seen by some observers as an example of racial prejudice. The investigation of Chi Mak—followed by the successful investigation and prosecution of Greg Chung—turned out to be a milestone in the F.B.I.’s efforts against Chinese espionage, and demonstrated that Chinese spies had indeed been stealing U.S. technological secrets.

While Chung volunteered his services to China out of what seemed to be love for his motherland, the F.B.I. believed that Mak was a trained operative who had been planted in the U.S. by Chinese intelligence. Beginning in 1988, Mak had worked at Power Paragon, a defense company in Anaheim, California, that developed power systems for the U.S. Navy. The F.B.I. suspected that Mak, who immigrated to the U.S. from Hong Kong in the late nineteen-seventies, had been passing sensitive military technology to China for years.

The investigation began when the F.B.I. was tipped off to a potential espionage threat at Power Paragon. The case was assigned to a special agent named James Gaylord; since the technologies at risk involved the Navy, Gaylord and his F.B.I. colleagues were joined by agents from the Naval Criminal Investigation Service. Mak was put under extensive surveillance: the investigators installed a hidden camera outside his home, in Downey, California, to monitor his comings and goings, and surveillance teams followed him wherever he went. All of his phone calls were recorded.

A short and energetic sixty-four-year-old with a quick smile, Mak was a model employee at Power Paragon. Other workers at the company often turned to him for help in solving problems, and Mak provided it with the enthusiasm of a man who appeared to live for engineering. His assimilation into American life was limited to the workplace: he and his wife, Rebecca, led a quiet life, never socializing with neighbors. Rebecca was a sullen, stern woman whose proficiency in English had remained poor during her two and a half decades in the United States. She never went anywhere without Mak, except to take a walk around the neighborhood in the morning.

Sitting around the house—secret audio recordings would later show—the two often talked about Chinese politics, remarking that Mao, like Stalin, was misunderstood by history. The influence of Maoist ideology was, perhaps, evident in the Maks’ extreme frugality: they ate their meals off of newspapers, which they would roll up and toss in the garbage. Every Saturday morning, after a game of tennis, they drove to a gas station and washed their car using the mops and towels there. From the gas station, the Maks drove to a hardware store and disappeared into the lumber section for ten minutes, never buying anything. For weeks, the agents following them wondered if the Maks were making a dead drop, but it turned out that the lumber section offered free coffee at that hour.

* * *

One evening in September, 2004, Gaylord drove to a playground next to the freeway in Downey. About two dozen of Gaylord’s colleagues from the F.B.I. were already gathered there, including a team from the East Coast that specialized in making clandestine entries into the homes of investigation suspects. That night, they planned to conduct a secret search of Mak’s house. Mak and Rebecca were vacationing in Alaska, and this gave agents an opportunity to use a court order authorizing them to enter the Maks’ residence in their absence.

For weeks, agents had been watching Blandwood Road, the street the Maks lived on, researching the nightly patterns of nearby neighbors. The person next door routinely woke up at three to go to the bathroom, walking past a window that offered a partial view into the Maks’ house. Behind the Maks’ residence was a dog that was given to barking loudly. A neighbor across the street came out every morning at four to smoke a cigarette. If any of them were to raise an alarm, the search would not remain secret. Mak would find out and, if he was indeed a spy, it would become harder to find evidence against him.

Shortly before midnight, Gaylord and two other agents got into a Chevy minivan with the middle and back rows of seats removed. The vehicle was identical in appearance to the one that Mak drove; it would raise no suspicions even if neighbors happened to notice it. The agents lay down flat in the back of the van, leaving only the driver visible from the street. After getting the go-ahead from a surveillance team, the van pulled out from the playground and drove to Blandwood Road, stopping a short distance from the Maks’ house.

The group of entry specialists was already inside the house. Gaylord gently opened the front door and entered, letting two other agents in behind him. The men stood motionless, waiting for their eyes to adjust to the darkness. Everything they could see was covered in a thick layer of dust, including a model airplane on a coffee table and a vacuum cleaner in the hallway. In the dim light, Gaylord saw stacks of documents, some two to three feet high, everywhere: by the front door, on the dinner table, in the home office.

The agents began photographing the documents, taking care to put them back exactly as they had been. Among the stacks were manuals and designs for power systems on U.S. Navy ships and concepts for new naval technologies under development. One set of documents contained information about the Virginia-class submarines, describing ways to cloak submarine propellers and fire anti-aircraft weapons underwater.

The agents took pictures of other materials: tax returns, travel documents, and an address book listing Mak’s contacts, including several other engineers of Chinese origin living in California. This is where the F.B.I. first came across the name Greg Chung.

* * *

The F.B.I. was also watching Chi Mak’s younger brother, Tai Mak, who had moved to the U.S. from Hong Kong in 2001. Tai was a broadcast engineer for a Hong Kong-based satellite-television channel, Phoenix TV, which is partly owned by the Chinese government. He lived in Alhambra, about twelve miles from Downey, with his wife, Fuk Li, and their two teen-age children, Billy and Shirley.

Fuk and Rebecca didn’t get along, and would bad-mouth each other to their husbands. Still, the two families got together every few weeks, usually at a Chinese restaurant in Alhambra, which has a large Chinese-American population. A frequent topic of conversation was Fuk’s aging mother, who lived alone in Guangzhou. Fuk and Tai were concerned about her health, and they depended on a family friend named Pu Pei-liang, a scholar at the Center for Asia Pacific Studies at Sun Yat-sen University, to check on her periodically.

Every week, agents inspected the trash from both families’ houses, after offloading it from a garbage truck. “It’s not a fun duty, especially in the summertime, here in California,” Gaylord told me. The job fell mostly to Gaylord’s younger colleagues, who would lay the garbage out in a parking lot or a garage and rummage through it.

The trash searches and the surveillance went on for months, but they yielded no evidence. “I never said it, but I thought, Wow, we’re using a lot of resources, but we haven’t proved anything yet,” Gaylord told me. Then, one day in February, 2005, Jessie Murray, an agent who spoke Mandarin, found several torn-up bits of paper with Chinese text while going through Chi and Rebecca’s trash. She put them in a Ziploc bag and brought them to the office.

The agents assembled the contents of the bag like a jigsaw puzzle. Patched together, the pieces constituted two documents, one handwritten and the other machine-printed. Gunnar Newquist, an investigator assigned to the case by the N.C.I.S., spotted an English phrase at the bottom of the handwritten sheet. “DDX,” he said, reading it aloud. “That’s a Navy destroyer.”

The handwritten text turned out to be a list of naval technologies and programs: submarine propulsion networks; systems for defending against nuclear, chemical, and biological attacks; and others. On the printed sheet were instructions about going to conferences to collect information. Gaylord was certain that the two documents were tasking lists from Chinese intelligence.

In October, the F.B.I. made another covert entry into Chi Mak’s house and installed a hidden camera above the dining-room table; the surveillance video from that camera can be seen below. Days later, on a Sunday morning, agents observed Mak sitting at the table, inserting CDs into a laptop and talking to Rebecca about the information that he was copying. All of it related to the Navy, including a paper about developing a quieter motor for submarines, a project that Mak was in charge of at Power Paragon.

Combing through translated phone conversations from the previous week, investigators learned that Fuk and Tai were planning to leave California for China the following Friday. They discovered a call that Tai had made to Pu, the family friend in Guangzhou, which Tai began with a strange introduction: “I am with Red Flower of North America.” Tai told Pu that he was coming to China for the spring trade show, and that he was bringing an assistant. Pu asked him to call upon arriving at the Guangzhou airport, using a phone card that Pu had given him earlier. Tai was clearly speaking in code: he wasn’t connected to any organization named Red Flower, and it was autumn, not spring.

The following day, Tai and Fuk talked about the upcoming trip. Fuk asked if they would have to carry a heavy load of documents from Chi Mak, as they had done in the past. Tai assured her that, this time, they only needed to put the information on disks, using the computer that Pu had given them.

Fuk and Tai were arrested at the Los Angeles airport after security agents searched their luggage and found an encrypted disk containing the files that Chi Mak had copied. On the same night, F.B.I. agents arrested Chi and Rebecca Mak just as they were preparing for bed. The two sat silently on the couch while agents searched the house, for the first time with the lights turned on.

* * *

During a six-week jury trial in 2007, government prosecutors painted Chi Mak as a trained spy who started his career as an intelligence officer for the Chinese government during his years in Hong Kong. Mak’s first assignment, according to the prosecution, was monitoring the movements of U.S. Navy ships entering and leaving the Hong Kong harbor during the Vietnam War, a job that Mak performed assiduously while working at his sister’s tailor shop. Gunnar Newquist testified that, in an interview given to Newquist and a fellow N.C.I.S. agent shortly after his arrest, Mak had confessed to sending information about commercial and military technologies to China since the early eighties. Mak denied making any such confession.

On May 10, 2007, the jury convicted Mak on charges of conspiring to export U.S. military technology to China and acting as an unregistered agent of a foreign government. Weeks later, Tai, Fuk, and their son, Billy, pleaded guilty to being part of the conspiracy. Rebecca Mak pleaded guilty to being an unregistered foreign agent. Mak was sentenced to twenty-four and a half years; Tai received a sentence of ten years. Fuk and Billy were deported to China, as was Rebecca—after she had spent three years in prison.

When I went to see Mak, last summer, at the Federal Correctional Institution, in Lompoc, California, a minimum-security prison near Vandenberg Air Force Base, he denied that he had ever worked for Chinese intelligence. Mak also insisted that Chung hadn’t spied for China, either. He said that they had both been unfairly targeted by investigators, as part of a politically motivated campaign against China by U.S. law enforcement agencies. The reason he’d come to the U.S. in the seventies, Mak said, was not to work as a sleeper agent—as the prosecution had claimed—but to advance professionally and to see the world. At one point, he caught himself going on at length about an aircraft-powering generator he had helped to design in the eighties. “When I talk technical, I get excited,” he said, grinning sheepishly.

His enthusiasm waned when I asked him about the list of military technologies that the F.B.I. had recovered from his trash. He told me that he’d found it inside a book on Chinese medicine that his nephew, Billy, brought back for him from a trip to China. “Maybe somebody was trying to take advantage of Billy,” he said. When I pressed him to guess who the sender of the list might have been, Mak got fidgety and grim. “It could have been Pu Pei-liang,” he said, finally. He insisted that the only thing he’d ever done with the list was tear it up.

Mak acknowledged that he’d sent papers to Pu in the past, but said that they were all from the open literature. The CDs he’d given to Tai before Tai’s aborted trip to China didn’t contain anything sensitive, either, he said, alleging that the prosecution had greatly exaggerated their importance. Still, I asked, who were the CDs meant for? Mak narrowed his eyes, as if trying hard to remember. “I’m not too sure,” he said. “I’m not too sure.”